Update dart:chrome to include fileSystem, and update summary docs.

sdk/lib/chrome/dart2js/chrome_dart2js.dart

-/// Native wrappers for the Chrome Packaged App APIs.
+/// Native wrappers for the Chrome packaged app APIs.
 ///
-/// These functions allow direct access to the Packaged App APIs, allowing
-/// Chrome Packaged Apps to be written using Dart.
+/// These functions allow direct access to the chrome.* APIs, allowing
+/// Chrome packaged apps to be written using Dart.
 ///
-/// For more information on these APIs, see the Chrome.* APIs Documentation:
-///   http://developer.chrome.com/extensions/api_index.html
+/// For more information on these APIs, see the
+/// [chrome.* API documentation](http://developer.chrome.com/apps/api_index.html).
 library chrome;
 
 import 'dart:_foreign_helper' show JS;
 import 'dart:_js_helper';
 import 'dart:html_common';
 import 'dart:html';
 
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
@@ skipping 338 matching lines @@
 class API_Chrome {
   /*
    * JS Variable
    */
   Object _jsObject;
 
   /*
    * Members
    */
   API_ChromeApp app;
+  API_file_system fileSystem;
 
   /*
    * Constructor
    */
   API_Chrome() {
     this._jsObject = JS("Object", "chrome");
     if (this._jsObject == null)
       throw new UnsupportedError('Not supported by current browser.');
 
     var app_object = JS('', '#.app', this._jsObject);
     if (app_object == null)
       throw new UnsupportedError('Not supported by current browser.');
     app = new API_ChromeApp(app_object);
+
+    var file_system_object = JS('', '#.fileSystem', this._jsObject);
+    if (file_system_object == null)
+      throw new UnsupportedError('Not supported by current browser.');
+    fileSystem = new API_file_system(file_system_object);
   }
 }
 
 // The final chrome objects
 final API_Chrome chrome = new API_Chrome();
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Generated from namespace: app.window
@@ skipping 848 matching lines @@
   /// given file entry. Only the 500 most recently used entries are retained,
   /// where calls to retainEntry and restoreEntry count as use. If the app has
   /// the 'retainEntries' permission under 'fileSystem', entries are retained
   /// indefinitely. Otherwise, entries are retained only while the app is running
   /// and across restarts.
   String retainEntry(FileEntry fileEntry) => JS('String', '#.retainEntry(#)', this._jsObject, convertArgument(fileEntry));
 
   API_file_system(this._jsObject) {
   }
 }